/*
 * Copyright (C) 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.codemirror2_gwt.client;

import com.google.gwt.dom.client.NativeEvent;

/**
 * Interface used for dealing with codemirror's keyHook option in java.
 *
 * @author Nikhil Singhal
 */
public interface KeyEventHandler {

  /**
   * This function is invoked everytime codemirror encounters a key event. You can do any processing
   * you need in this function, and then optionally ask codemirror to completely ignore the event
   * based on the return value.
   *
   * @return Return true if you want codemirror to not handle this event, false if you want normal
   *   handling to occur.
   */
  boolean onKeyEvent(NativeEvent e);

  /**
   * Returns a {@link KeyEventHandler} that does nothing.
   */
  KeyEventHandler NO_OP_KEY_HANDLER = new KeyEventHandler() {
    @Override public boolean onKeyEvent(NativeEvent e) {
      return false;
    }
  };
}
